[FFmpeg-devel] Channel layouts for aac encoding/decoding and vorbis decoding

Benjamin Larsson banan
Mon Aug 10 15:29:37 CEST 2009


Jason Tackaberry wrote:
> On Mon, 2009-08-10 at 11:45 +0200, Benjamin Larsson wrote:
>> The internal ffmpeg channel order that is used is based on the wav file
>> order.
>>
>> http://msdn.microsoft.com/en-us/library/ms713496(VS.85).aspx
> 
> Which, for 6 channels at least, is the same as the SMPTE-ITU-R order.
> But the order defined by Microsoft seems to be more thorough, so it's
> good to know that's the reference.
> 
> Now, when you say "internal," do you mean "completely transparent to the
> API caller?"  Because I'm more inquiring about the order that is visible
> to me as the user of the API (and specifically which layout goes into
> and comes out of AAC and Vorbis codecs).
> 
> Thanks,
> Jason.

The FFmpeg codecs should use that layout for output and input. Though
there are still some codecs that do not adhere to that.

MvH
Benjamin Larsson



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